Redox flow batteries, which are known as large-capacity storage batteries, include redox flow batteries that use strongly acidic aqueous solutions typified by vanadium-based redox flow batteries.
Patent Document 1 discloses the use of a gas phase method carbon fiber for the electrode material of a redox flow battery. Patent Document 2 describes a carbon fiber felt having voids formed within the interior of the felt, which can be used as an electrode material that suffers little pressure loss when an electrolyte passes through the electrode, and exhibits good conductivity in the thickness direction. Further, Patent Document 3 discloses a redox flow battery having a structure in which a porous sheet material formed from a material that is softer than the material that constitutes the electrodes is provided between the ion exchange membrane and the electrodes.